а) 16y²-0,25=(4y-0.5)(4y+0.5)
б) a²+ 10ab + 25b²=(a+5b)(a+5b)
=a³-2a²+2²a+2*(a²-2a+2²)=a³-2a²+4a+2a²-4a+8=a³+8=a³+2³.
⁴√ 15 5/8 = ⁴√125/8 = (( 5/2 )³ ) ^ 1/4 = 5/2 ^ 3/4
⁴√ 2/5 = 2/5 ^ 1/4 = 5/2 ^ - 1/4
( 5/2 ^ 3/4 ) : ( 5/2 ^ - 1/4 ) = 5/2 ^ 4/4 = 5/2 = 2,5
Ответ 2,5
(а+b)³=a³+3a²b+3ab²+b³
(2x+3)³-8х³=36х²
(2х)³+3*(2х)²*3+3*2х*3²+3³-8х³=36х²
8х³+36х²+54х+27-8х³=36х²
8х³-8х³+36х²-36х²+54х+27=0
54х=-27
х=-27:(-54)
х=-0,5